Blast device for furnaces.



No. 698,525. Patented Apr. 29, I902.

C. P. LARSEN.

BLAST'DEVICE FOR FURNACES.

(Application filed June 3, 1901.) (No Model.) 2SheetsSheet I.

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No. 698,525. Patented Apr. 29, i902;

C. P. LARSEN.

BLAST DEVICE FOR FURNACES.

(Application filed June 3,1901.) (No Model.) 2 Sheets-$hoet 2.

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UNITED ST TES PATENT OFFICE.

[oARL 1 LARSEN, OF-RUSH orrY, MINNESOTA.

BLAISTDEVICE FOR FURNACES.

SPECIFICATION forming part of Letters Patent No. 698,525, dated April 29, 1902.

Application filed'June 3, 1901. Serial No. 62,847. (No model.)

To all whom it may concern.-

Be it known that I, CARL'P. LARSEN, a citizen of the United States, residing at Rush City, in the county of O hisago and State of Minnesota, have invented certain new and useful Improvements inBlas'tDevices for Furnaces; and I do herebyldeclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has for its object to improve the construction of under-grate combined air and steam blowers for furnaces; and to this end it consists of the novel devices and combinations of devices hereinafter described, and defined in the claims. It is a well-known fact that these under-grate combined steam and air blowers are by far the most eflicient devices so far devised for burning cheap grades of anthracite and bituminous fuels, such as the grades known as buckwheat, rice, screenings, slack, &c.; but in all these devices as hitherto constructed the amount of air delivered has beenproportionate to or dependent on the amount of steam, or vice versa. that various grades of fuel require different proportions of steam and air to obtain the best results. Forinstance, when the fuel contains a largeamount of slag or cinders a rela tively large amount of steam in proportion to the air is required in order to soften, disintegrate, and burn the same. In fact, I believe I am the first to accomplish the burning of the slag or cinders in a satisfactory manner, and this I am able to accomplish by an arrangement whereby theproportionate This is a defect, for the reason position. Fig. 2 is a transverse vertical section on the line m m of Fig. 1. Fig. 3 is a vertical section on the line :0 m of Fig. 2. Fig. 4

is a detail in section on the line m m of Fig. 3. Fig. 5 is a plan view of one of the blades of the impact-wheel, and Fig. 6 is a detail in sec tion on the line 00 w of Fig. 2. i

The numeral 1 indicatesan ordinary horizontal boiler supported by furnace-walls 2 in the ordinary manner.

The numeral 3 indicates the f urnace-grate, above which is the combustion-chamber 4 and below which is the ash-pit 5.

The numeral 6 indicates an ordinary fancase suitably secured outside of the furnace and provided with ordinary air-inlets 7 and with a blast-tube 8, which leads therefrom and opens into the ash-pit5 at a suitable point below the grate 3. A fan 9, the shaft 10 of which works in suitable bearings 11, works in the fan-case 6. An impact-wheel 12, provided with peripheral blades 13, is also secured on the shaft 10. Said impact-wheel 12 works within a case or housing 14, which is provided at one side with a neck or tubular extension 15, which terminates in position to discharge the steam into the fan-case 6 16, shown asprovided with a finger-piece 17, by means of which it may be easily adjusted.

The discharge end or nozzle 18 of avalved steam-supply pipe 19, having a valve 20, terminates in position to discharge a jet of steam tangentially of the wheel 12 and directly against its blades 13, as best shown in Fig. 3. In this preferred construction the said nozzle 18 opens into a fixed segmental trough 21, in whichthe propelling-blades 13 closely fit for ashort distance of movement while they are receiving the impact from the said steam-jet. From the outer and lower portion of the wheelhousing 14 an exhaust pipe 22, having a valve 23, leads to a suitable point of exhaust.

When the valve 20 of the steam-supply pipe 19 and the damper 16 of the neck 15 are opened and the valve 23 of the exhaust-pipe 22 is closed, the jet of steam delivered out of the impact-wheel will rotate the said wheel, together with the shaft 10 and fan 9. The fan through one eye or air-passage '7.thereof. In order to vary the opening at the end of the neck 15, it is provided with a damper or valve being rotated will drive a blast of air through the tube 8, and the suction thereby produced will carry with the blast the steam which is exhausted into the fan-case 6 through the neck 15. When the said valve 20 in the steampipe 19 and the valve 23 in the exhaust-pipe 22 are opened and the damper 16 in the neck is closed, it is evident that the fan will deliver a dry blast of air through the tubes, while the steam from the Wheel-housing 14 will be discharged through the exhaust-pipe 22. From these statements it is of course evident that by opening-the damper 1b and the exhaust-valve 23 more or less the commingled air and steam may be delivered through the pipes in anydesired relative proportions. Thestrengthof theblastdelivered through the said tube 8 may be varied by opening more or less the steam-supply pipe 20. In other words, as already stated, the intensity of the blast may be varied at will, and the proportionate amounts of mingled steam and air delivered to the furnace may be varied at will and independently oftheintensity of the blast.

In actual practice I have found the abovedescribed device to be extremely efficient and to be capable of burning in the most satisfactory manner cinders, slag, and other substances hitherto considered non-combustible, or practically so.

From the statements above made it will of course be understood that the device above describedis capable of considerable modification within the scope of my invention.

What I claim, and desire to secure by Letters Patent of the United States, is as follows: 1. The combination with a furnace, of a fan havinga fan-case with a blast-tube delivering to said furnace, below the grate thereof, an impact-wheel on the fan-shaft, a case inclosing said impact-wheel and provided.

case inclosing said impact-Wheel and provided with two valved discharge-passages, one of which delivers steam within and the other without the said fan-case, and a valved steam-supply pipe provided with a nozzle or discharge end terminated in position to discharge a jet of steam onto the blades of said impact-wheel, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

- CARL P. LARSEN. Witnesses:

HENRY MEYER, DAVID E. WESTLUND. 

